A number of sesquiterpene dilactones are known which have significant cytotoxic and anti-tumor properties. Because of the scarcity of these natural products and the complexity of their structures, general methods for their synthesis are highly desirable. We propose to design general methods for the synthesis of compounds of this class which will allow the production, in quantity, of not only the natural products, but many analogs as well. We propose synthetic studies of compounds of the elemane, germacrane, pseudoguianolide, and seco-eudesmane families.